My first one (1960s) was a leather sling designed to carry one's rifle on their back sling over the shoulder or setup a fixed shooting position on the range. Not for carrying one's rifle in front of them for immediate use or keep one's hands free. What's your preference? If you don't have one these YouTube videos offer a variety of opinions. When in Vietnam we would use the nylon sling with the blanket roll strap/para cord to extend length of sling. It was attached to front sight and butt stock sling swivel. Crude but it left one's hands free.